The present invention relates to a plasma marking torch which is capable of marking metal workpieces with lines, numbers or symbols.
Known plasma marking torches are commonly employed to mark metal plates and other workpieces with lines, numbers or symbols to facilitate subsequent plate layout and assembly operations. Also, alpha-numeric markings are sometimes employed for plate identification purposes. The known marking torches operate at low amperage (e.g., about 8-10 amps) and they employ a non-cutting gas, such as argon, as the plasma gas, which forms a plasma stream which exits through the nozzle bore and forms an etched plasma mark on the workpiece. The known marking torches also include an air cooling system whereby air is circulated into contact with the inner electrode and then along the outside surface of the torch nozzle so as to exit coaxially about the plasma stream.
It is an object of the present invention to provide a plasma marking torch of the described type which is capable of increased marking speed, and which is able to etch a line of narrow width so as to improve line definition.
It is also an object of the present invention to provide a torch of the described type which minimizes the burn back of the protective primer used on some carbon steel sheeting, and which provides improved cooling of the electrode and the other consumable components of the torch.
It is still another object of the present invention to provide a torch which has the capability of marking a workpiece as described above, but which also has the capability of being shifted to a different operating mode which is capable of cutting the workpiece.